Cutting device and related systems and methods

ABSTRACT

Systems, apparatus, and methods are described for forming an incision in tissue for receiving a surgical instrument. A cutting device for forming the incision can be reversibly coupleable to an instrument, e.g., a dilator. The instrument may define a lumen configured to receive a wire that extends or is otherwise extendable through a puncture site. The cutting device can include a cutting element configured to be actuated to form the incision such that the incision extends form the puncture site and is sized to receive the instrument.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Application No.PCT/US20/31047, filed May 1, 2020, which is a continuation of, andclaims priority to and the benefit of, U.S. patent application Ser. No.16/861,735, filed Apr. 29, 2020, titled “Cutting Device and RelatedSystems and Methods,” now issued as U.S. Pat. No. 10,813,665, which is acontinuation-in-part of U.S. patent application Ser. No. 16/834,068,filed Mar. 30, 2020, titled “Cutting Device and Related Systems andMethods,” now abandoned, which is a continuation of U.S. patentapplication Ser. No. 16/402,921, filed May 3, 2019 titled “CuttingDevice and Related Systems and Methods,” now U.S. Pat. No. 10,603,071,the disclosures of each of which are incorporated by reference herein.

International Application No. PCT/US20/31047 also claims priority to andthe benefit of U.S. patent application Ser. No. 16/834,068 and U.S.patent application Ser. No. 16/402,921.

TECHNICAL FIELD

The present disclosure relates generally to systems, apparatus, andmethods for deploying a medical instrument into a body lumen of asubject during a medical procedure, and in particular, to a cuttingdevice capable of forming an incision for receiving a medicalinstrument, such as a catheter, into a body lumen of a subject.

BACKGROUND

Intravascular medical devices such as catheters are deployed in manymedical procedures. Use of intravascular catheters, however, can lead tobloodstream infections, which can be costly to treat and/or result indeath or other health complications. For example, an infection canresult from skin organisms that migrate from an insertion site of acatheter onto and along an external surface of the catheter. Thismigration of skin organisms along the catheter which dwell within acentral vessel, artery, or vein, can lead to a blood stream infection.In many hospitals in the U.S. including high performing intensive careunits, this type of event occurs approximately 1-3 times every 1000central line days, and sometimes far more. Infections can also be tiedto use of other types of catheters placed for other reasons to providemedical care, including catheters such as dialysis catheters,cannulation catheters for extracorporeal membrane oxygenation (ECMO),and chest tubes placed within the pleural cavity.

A catheter or other intravascular medical device can be delivered intoblood vessels, organs, body cavities, and other anatomic sites (“targetsite(s)” or “target anatomical site(s)”) using a variety of techniques.One commonly used technique to gain access to a target site (e.g., ablood vessel) is the Seldinger technique. The Seldinger techniqueinvolves penetrating through skin tissue overlying a blood vessel of asubject with a sharp hollow object, typically a hollow needle. A wire(e.g., a guidewire) can then be advanced via a lumen of the needle intothe blood vessel, and the needle can be withdrawn over the guidewire andremoved.

Following placement of the wire but prior to insertion of the catheteror other intravascular device, an incision (e.g., “skin-nick,” in caseswhere the diameter of the catheter is small) in the skin tissue isformed through the skin at or adjacent to the opening formed by theneedle (i.e., the entry site for the wire). If formed properly, theincision will start at the opening or puncture site of the needle, andhave a length approximately equal to the diameter of the catheter to besubsequently inserted. After the incision is formed, the catheter orother medical instrument can then be passed over the wire, through theincision, and into the blood vessel or body cavity.

While techniques such as the Seldinger technique can be used to deploy acatheter or other medical instrument into a target site, such as a bloodvessel, they can be difficult and/or time-consuming to perform properly.For example, complications can occur with the creation of the incision,e.g., where the incision does not initiate at the opening of thepuncture site resulting in a skin-bridge, the incision is too large, orthe incision is too long. When these complications arise, it may beimpossible (or additional measures may be required) to insert thedilator or catheter (or other medical instrument(s)) over the Seldingerwire into the target vessel, such as in the case of a skin bridge).Alternatively, if an incision is too large, bleeding may occur aroundthe catheter, which can be substantial, or the incision itself, beingopen, can provide a site for colonization, either of which increases therisk of bacterial colonization at the catheter entry site, increasingthe risk of a blood stream infection. Accordingly, it is desirable tohave systems and methods that reduces the difficulty and/or skillrequired to gain access to a target site, thereby reducing complicationsassociated with use of any invasive catheter.

SUMMARY

According to an aspect of the present disclosure, an apparatus forforming a controlled incision in tissue is provided. The apparatus mayinclude a coupling mechanism (e.g., a reversible coupling mechanism)configured to couple the apparatus to a dilator having a tapered distalend and a hub at a proximal end. The dilator may define a lumenconfigured to receive a wire that extends or is otherwise extendablethrough a puncture site. The apparatus may further include a proximalend configured to abut the hub of the dilator when the apparatus iscoupled to the dilator. The apparatus may further include a cuttingelement including an inner edge and an outer cutting edge. The cuttingelement may be configured to be movable between a retracted position andan extended position, in which the inner edge extends along the tapereddistal end of the dilator. The outer cutting edge may be configured toform an incision extending from the puncture site, thereby preventingthe formation of a skin bridge. Furthermore, the cutting element can beconfigured to form an incision that has a length that is equal to adiameter of a catheter (or other medical instrument) that is insertedinto the incision.

According to an aspect of the present disclosure, a method for deployinga catheter or other medical instrument into a body lumen is provided.The method may include advancing a dilator, over a wire positionedthrough a puncture site formed in a tissue, toward the puncture site.The dilator may have a reversibly attached cutting device including acutting element configured to cut the tissue. The method may furtherinclude moving the cutting element from a retracted position to anextended position. The method may further include inserting the distalend of the dilator and the cutting element into the tissue such that thecutting element forms an incision extending from the puncture site andsized to receive a surgical instrument.

According to an aspect of the present disclosure, a kit including asystem for deploying a medical instrument is provided. The kit mayinclude a dilator defining a lumen configured to receive a wire thatextends or is otherwise extendable through a puncture site. The dilatormay include a hub at a proximal end and a tapered distal end. The kitmay further include a cutting device including a cutting elementconfigured to form an incision extending from the puncture site. Thecutting element may be configured to be movable between a retractedposition and an extended position. The cutting device may be configuredto be reversibly coupled to the dilator such that a portion of thecutting element extends to the distal end of the dilator when thecutting element is in the extended position.

It should be appreciated that all combinations of the foregoing conceptsand additional concepts discussed in greater detail below (provided suchconcepts are not mutually inconsistent or exclusive) are contemplated asbeing part of the inventive subject matter disclosed herein. Inparticular, all combinations of claimed subject matter appearing at theend of this disclosure are contemplated as being part of the inventivesubject matter disclosed herein. It should also be appreciated thatterminology explicitly employed herein that also may appear in anydisclosure incorporated by reference should be accorded a meaning mostconsistent with the particular concepts disclosed herein.

Other systems, processes, and features will become apparent to thoseskilled in the art upon examination of the following drawings anddetailed description. It is intended that all such additional systems,processes, and features be included within this description, be withinthe scope of the present disclosure, and be protected by theaccompanying claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings are not necessarily to scale. The drawings are merelyschematic representations, not intended to portray specific parametersof the invention. The drawings are intended to depict only typicalembodiments of disclosed systems, apparatus, and methods. In thedrawings, like reference characters refer to like elements (e.g.,functionally similar and/or structurally similar elements).

FIG. 1 is a schematic diagram depicting a cutting device, according toan embodiment.

FIG. 2 is a schematic diagram depicting a cutting device and a medicaldevice with which the cutting device can be used, according to anembodiment.

FIG. 3 is a flow diagram illustrating a method of performing a medicalprocedure on a subject using a cutting device, according to anembodiment.

FIG. 4 is a schematic diagram depicting a kit including a cuttingdevice, according to an embodiment.

FIG. 5 depicts a perspective view of a cutting device, according to anembodiment.

FIG. 6 depicts a top view of the cutting device shown in FIG. 5,according to an embodiment.

FIG. 7 depicts a cross-sectional view of the cutting device shown inFIG. 5, taken along A-A as shown in FIG. 6, according to an embodiment.

FIG. 8 depicts a cross-sectional view of the cutting device shown inFIG. 5, taken along A-A as shown in FIG. 6, according to an embodiment.

FIG. 9 depicts a perspective view of the cutting device shown in FIG. 5while attached to a medical device, according to an embodiment.

FIG. 10 depicts a side view of the cutting device shown in FIG. 5 whileattached to a medical device, according to an embodiment.

FIG. 11 depicts an exploded view of the cutting device shown in FIG. 5,according to an embodiment.

FIG. 12A depicts a side view of a cutting device, according to anembodiment.

FIG. 12B depicts an enlarged view of a distal end of an instrument usedwith the cutting device depicted in FIG. 12A, according to anembodiment. FIG. 12C depicts a cross-sectional view taken along a lineB-B in FIG. 12B.

FIG. 13 depicts a side view of a cutting device, according to anembodiment.

FIGS. 14A-14C depict enlarged views of a distal end of the cuttingdevice shown in FIG. 13, according to an embodiment.

FIG. 15 depicts a view of a distal end of the cutting device shown inFIG. 13 forming an incision around a guidewire, according to anembodiment.

FIGS. 16A-16D depict side views of a cutting device in differentconfigurations, according to an embodiment.

FIGS. 17A and 17B schematically depict a puncture site and incisionalong a skin surface.

FIG. 18 depicts a perspective view of a cutting device, according toembodiments.

FIG. 19 depicts an exploded view of the cutting device shown in FIG. 18,according to embodiments.

FIG. 20 depicts a view of a distal end of the cutting device shown inFIG. 18, according to embodiments.

FIGS. 21 and 22 depict a cross-sectional view of the cutting deviceshown in FIG. 18, taken along B-B as shown in FIG. 20, according toembodiments. FIG. 21 depicts a cutting element of the cutting device ina first, extended configuration, and FIG. 2 depicts the cutting elementin a second, retracted configuration.

FIG. 23 depicts another cross-sectional view of the cutting device shownin FIG. 18, with certain components depicted transparently to show alocking mechanism of the device, according to embodiments.

DETAILED DESCRIPTION

Embodiments of the present disclosure are directed to systems,apparatus, and methods for providing access to a target site (e.g., ablood vessel) such that a medical instrument, e.g., a catheter, can bedeployed in the target site. Specifically, systems, apparatus, andmethods described herein can be used to form an incision in tissue of asubject during a vascular access procedure and/or other proceduresinvolving placement of a medical device into a body cavity.

Vascular access procedures, such as, for example, the Seldingertechnique, can be used to provide access to a target body lumen (e.g.,vessel, pleural space) by deploying a medical instrument (e.g., acatheter) into the target body lumen. For example, when the Seldingertechnique is used, a target body lumen (e.g., vessel, pleural space) maybe accessed percutaneously by puncturing skin of the subject with ahollow needle, inserting a guidewire through the hollow needle so as toposition the distal end of the guidewire in the target body lumen. Theneedle can be withdrawn, leaving the wire in place. To accommodate aplacement of a catheter or other medical instrument, the diameter of theskin puncture site traversed by the wire can be enlarged or dilated. Toaccomplish this, the operator can create a skin incision extending fromthe puncture site and having a length equal to the diameter of thecatheter or other medical instrument. Once that incision is formed, adilator (or one or more increasingly larger dilators) is passed over theSeldinger wire, creating a track (e.g., opening) suitable to accommodatethe final catheter or medical instrument to be inserted into the targetbody lumen.

The incision can be formed using a cutting device, such as, for example,a blade or scalpel, to form the incision. The physician can hold theguidewire using one hand, and the cutting device using his or her otherhand, and then via visual guidance, create the incision, which canreceive the dilator, catheter, and/or other medical instrument. Ifproperly performed (e.g., if the incision is properly created orformed), the incision extends from the puncture site and has a lengthequal to but not longer than the diameter of the catheter or otherinstrument to be inserted through the incision. Complications, however,can arise when the incision is not properly formed. For example, whenthe incision is too long, it allows leakage of bodily fluids around thecatheter when it is positioned, compromising the ability of the skin tofunction as a barrier to infection. For example, an incision too longcompromises the ability of the skin to form a biological seal around thecatheter, which would normally prevent migration of bacteria or otherdisease-causing agents into the target body lumen. Furthermore, anoversized incision allows blood to leak out around the catheter skinentry site, which can be substantial, particularly in situations where asubject has received an anticoagulant. In these cases, the incision mayrequire stitches to better approximate the skin against the catheter soas to prevent bleeding.

As another example, if the incision does not involve the entry site madeby the needle (i.e., in which the Seldinger wire sits), but leaves askin bridge between the incision and the initial entry site created bythe needle, the ensuing dilator and/or other medical instrument can beprevented from being passed along the wire and through the entry site.FIG. 17A schematically illustrates cases where a skin bridge can form.As depicted, skin bridges 1774, 1778 can form when an incision 1772,1774 does not overlap with an opening of the puncture site 1770. Forexample, a skin bridge 1774 can form when an incision 1772 does notinitiate at the puncture site 1770, even if that incision is alignedwith the puncture site 1770. And a skin bridge 1778 can form when anincision 1776 is offset from the puncture site 1770 (e.g., not alignedwith the puncture site 1770). These skin bridges 1774, 1778 can preventa dilator or other instrument from being inserted into the skin. Inpractice, a physician may move a guidewire after forming the incision1772 to determine whether there is a skin bridge 1774, 1778, e.g., byvisibly inspecting whether the guidewire appears to be moving along alength of the incision. But with skin having some elasticity and withpoor visibility surrounding the puncture site (e.g., caused by bloodpooling around the puncture site and incision), it may not be possibleto determine whether a skin bridge has formed even if it appears theguidewire is moving along the incision. If a physician fails to identifythat there is a skin bridge 1774, 1778 and pushes a dilator or otherinstrument down along the guidewire (e.g., forces a dilator or otherinstrument down on the guidewire), the physician can bend or damage theguidewire. Then, even if the physician were to detect the skin bridge1774, 1778 and cut it away, e.g., with a second incision, the bentguidewire can prevent the dilator or other instrument from beinginserted into the skin. The second incision combined with the firstincision 1772, 1776 can also lead to an incision size that is not sizedto that of the dilator or other instrument, which as detailed above, canlead to migration of bacteria. Therefore, when complications arise witha skin bridge, the physician may have no other option than to remove theguidewire and restart the procedure. Systems, devices, and methodsdescribed herein are designed to prevent the formation of a skin bridge,i.e., by ensuring that an incision extends from a puncture site, asdepicted in FIG. 17B with incision 1772′ extending from puncture site1770. Further details of such systems, devices, and methods are providedbelow.

Similarly, if the incisional length is too short, the dilator and/orother medical instrument can be prevented from passing deeper than thelevel of the skin. In particular, if the incision does not extend fromthe puncture site, a skin-bridge can result. The skin bridge can preventthe catheter from being properly inserted into the target body lumen(i.e., because the skin bridge separates the puncture site from theincision), leading to bending of the Seldinger wire, and preventing itsuse as the dilator may not be able to pass over the bent wire, evenafter the skin bridge has been, by necessity, incised. And if theincision is too long, this can prevent the skin or tissue surroundingthe opening from sealing around the catheter or instrument, which canenable disease-causing agents (e.g., microorganisms, bacteria, viruses)to migrate along an external surface of the catheter into the targetbody lumen.

In the situations described above, if the problem is initiallyunrecognized, forcing the dilator can bend the wire or damage thedilator and/or other medical instrument, which can require thedeployment procedure to be repeated. Repeating the deployment procedurecan involve repeated accessing of the vessel or body cavity, with itsinherent dangers and patient discomfort, and/or the need of a new wireand/or insertion kit.

Systems, apparatus, and methods described herein can reduce the risk ofcomplications resulting from placement of a catheter or other instrumentinto a body lumen. As further described below, a cutting device can bedesigned to consistently form a controlled incision in skin thataddresses the aforementioned problems, allowing for placement of thedesired catheter or instrument into a body lumen without complications.

As illustrated schematically in FIG. 1, an example cutting device 100can include a housing 102, a cutting element 110, and a couplingmechanism 106. The example cutting device 100 can be placed proximate toa skin 170 of a subject and used to form an incision in the skin 170,e.g., by moving the cutting element 110 through the skin 170. Thehousing 102 can support the cutting element 110 and optionally includean actuation assembly or mechanism 104 designed to actuate the cuttingelement 110 to form the desired incision in the skin 170.

In some embodiments, the housing 102 can define a volume, recess, orarea for housing the cutting element 110 in a retracted or undeployedposition such that a cutting surface of the cutting element 110 isshielded when the cutting element is not in use. The actuation assembly104 can be designed to move the cutting element 110 forward, e.g., asschematically depicted using arrow 166, to position the cutting element110 in an extended or deployed position, such that the cutting element110 can form an incision in the skin 170. The actuation assembly 104 caninclude one or more actuation mechanisms for deploying the cuttingelement 110, i.e., for moving the cutting element 110 from an undeployedposition into a deployed position, as well as allowing for differentialincision lengths. In some embodiments, the actuation assembly 104 caninclude mechanical components for deploying the cutting element 110. Forexample, the actuation mechanism 104 can include a trigger that can beactuated to release a pre-loaded spring or other elastic component thatcan generate a force to deploy the cutting element 110. In someembodiments, the actuation assembly 104 can include a movable componentor actuator (e.g., a slider, button, tab, lever) that can be moved(e.g., slid along a length of the housing 102) to deploy the cuttingelement 110. In some embodiments, the actuation mechanism 104 caninclude electrically powered components (e.g., components driven and/orpowered by a battery or other power source) for deploying the cuttingelement 110. In some embodiments, the actuation assembly 104 can includecomponents driven mechanically, electrically, magnetically,pneumatically, hydraulically, etc.

The cutting element 110 can include one or more cutting surfaces orblades that are designed to penetrate through the skin 170 to form anincision. Alternatively or additionally, the cutting element 110 caninclude other mechanisms, e.g., a drill, an electrode, etc., for cuttingthrough the skin 170. The cutting element 110 can be coupled to (e.g.,mounted to) housing 102 in a fixed or movable relation, e.g., allowingfor a variable length incision. Furthermore, in some embodiments, thecutting element 110 can be movably coupled to housing 102 such that itcan move between an undeployed position and a deployed position, e.g.,as represented by arrow 166. In some embodiments, the cutting element110 can be removably coupled to housing 102. For example, the cuttingelement 110 can be designed to be removed or detached from housing 102,such that the cutting element 110 can be replaced after a single orlimited number of uses. In some embodiments, the cutting element 110and/or housing 102 can be disposable components that can be disposed ofafter a single use, e.g., after being used to provide access to a targetsite in the subject.

The housing 102 can be ergonomically shaped such that a user (e.g., aphysician) can hold (e.g., grip) the housing 102 in single hand.Optionally, if the actuation assembly 104 is present, the actuationassembly 104 can be positioned on or about the housing 102 such that theuser can actuate the actuation assembly 104 while maintaining his hold(e.g., grip) on the housing 102 with a single hand. For example, theactuation assembly 104 can be a slide that can be moved, e.g., using athumb of a user, to actuate the cutting element 110 during a medicalprocedure. The housing 102 and cutting element 110 can be formed fromlightweight material such that a user can comfortably hold the housing102 and cutting element 110 without feeling additional strain during amedical procedure.

The cutting device 100 can include a depth control element 108 that isintegrated into and/or coupled to the housing 102 and/or cutting element110. The depth control element 108 can be designed to limit a depth ofpenetration or insertion of the cutting element 110 into the skin 170 soas to control a size of the incision formed by the cutting element 110in the skin 170. In some embodiments, the depth control element 108 canbe designed to contact a surface of the skin 170 to control a depth ofinsertion of the cutting element 110. For example, the depth controlelement 108 can include a surface, protrusion, or other physicalstructure that can be disposed at a point along the cutting element 110and/or housing 102 such that it would contact a surface of the skin 170when the cutting element 110 has been inserted a predetermined depthinto the skin 170. In some embodiments, the depth control element 108can include one or more components that restrict movement of the cuttingelement 110, thereby controlling a depth of insertion of the cuttingelement 110. For example, the depth control element 108 can include oneor more protrusions and/or surfaces that interfere (e.g., lock) with oneanother to prevent further movement of the cutting element 110 in adirection toward the skin 170 after the cutting element 110 haspenetrated a predetermined depth into the skin. In some embodiments, thedepth control element 108 can include one or more sensor(s) (e.g., alight sensor, a pressure sensor, etc.) that can be designed to sense ordetect a depth of insertion.

The coupling mechanism 106 can include one or more components designedto couple the housing 102 (or other components of the cutting device100) to an instrument (e.g., a dilator, a catheter, etc.). In someembodiments, the coupling mechanism 106 can be designed to reversiblycouple the housing 106 to the instrument. For example, the couplingmechanism 106 can be designed to couple and decouple the housing 106 tothe instrument and/or additional instruments, as many times as neededwithout comprising its structure. In some embodiments, the couplingmechanism 106 can include mechanical components, e.g., a clasp, a clip,etc. that can attach around the instrument to couple the housing 102 tothe instrument. The mechanical component can be designed to be flexiblesuch that it can bend to fit around (e.g., grip onto) the instrument.Alternatively or additionally, the mechanical component can be designedto be mechanically biased (e.g., with a spring) or electrically drivento change between different configurations for attaching to and/ordetaching from the instrument. The coupling mechanism 106 can beconfigured to maintain the coupling between the housing 102 and theinstrument by interference fit, press fit, friction fit, and the like.In some embodiments, the coupling mechanism 106 can be configured toallow coaxial movement of the instrument such that the housing 102 (andother components of the cutting device 100) can slide or move along alength of the instrument. The coupling mechanism 106 can be integratedinto or attached to the housing 102. As further described with referenceto FIG. 2, the coupling mechanism 106 can be configured to attach thehousing 102 (or other components of the cutting device 100) to theinstrument such that the cutting element 110 is positioned to create anincision in the skin 170 for receiving the desired instrument. In someembodiments, the coupling mechanism 106 can be sized to a specific sizeof instrument. Alternatively, the coupling mechanism 106 can beconfigured to couple to instruments within a range of sizes, e.g., suchas with adjustable components (e.g., an adjustable clamp or a deformableplug that accommodates a range of sizes).

In some embodiments, a positioning element 120 can optionally be usedwith the cutting device 100 to assist with proper positioning of thedevice along a length of the instrument. For example, the positioningelement 120 can be designed to couple (e.g., attach) to the instrument,e.g., via a coupling element (e.g., coupling element 122), and extendalong a length of the instrument to indicate the location at which thecutting device 100 should attach to the instrument. When used with thecutting device 100, the positioning element 120 can prevent the cuttingdevice 100 from being attached to the instrument at a position that doesnot enable the cutting instrument to form a properly sized incision inthe tissue 170. In some embodiments, the positioning element 120 can bea spacer configured to extend from a proximal end or portion of theinstrument to the location at which the cutting device 100 is designedto attach to the instrument, as further described with reference to FIG.2.

The coupling mechanism 122 can be structurally and/or functionallysimilar to the coupling mechanism 106, but is designed to couple thepositioning element 120 to the instrument, as represented by line 262.For example, the coupling mechanism 122 can include a mechanicalcomponent (e.g., a clip or clasp) that is designed to reversibly couple(e.g., couple and decouple multiple times) the positioning element 120to the instrument such as by interference fit, press fit, friction fit,and the like. The coupling mechanism 122 can be integrated into orattached to the positioning element 120 so as to enable and facilitatereversible coupling of the positioning element 120 to the instrument,such as described herein. The positioning element 120 and the housing102 can be separately and individually attachable to and removable fromthe instrument.

In some embodiments, as an alternative to having a separate positioningelement (e.g., positioning element 120), the cutting device 100 caninclude a component (e.g., a protrusion) that can assist withpositioning the cutting device 100 along a length of the instrument. Forexample, the cutting device 100 can include a beam, rod, or other likestructure that can be configured to extend from a proximal end of thehousing 102 to a proximal end or portion of the instrument, such thatwhen the cutting device 102 is attached to the instrument (e.g., via thecoupling mechanism 106), such structure indicates the location at whichthe cutting device 100 should be positioned relative to the proximal ordistal end of the instrument.

The positioning of a cutting device relative to an instrument can befurther understood with reference to FIG. 2. As illustratedschematically in FIG. 2, an example cutting device 200 is shown inrelation to an example instrument 250 (e.g., a surgical instrument) withwhich the cutting device 200 can be used. The cutting device 200 can bestructurally and/or functionally similar to the cutting device 100. Forexample, the cutting device 200 can include a housing 202, a cuttingelement 210, and a coupling mechanism 206. The instrument 250 caninclude a hub 252 and a body 254. The cutting device 200 can bereversibly attachable to and/or supportable by the instrument 250, e.g.,via the coupling mechanism 206 attaching to the body 245 of theinstrument 250, as represented by line 264. The body 254 of theinstrument 250 can include portions that are rigid and/or flexible.

In some embodiments, the cutting device 200 can optionally include or beused with a positioning element 220. In some embodiments, positioningelement 220 can be a spacer that is configured to define the appropriatespacing between a proximal portion (e.g., hub 252) of the instrument 250and a proximal end of the housing 202 supporting the cutting element210. For example, the positioning element 220 can be configured tocouple to the body 254 of the instrument 250, e.g., via couplingmechanism 222, such that it extends from the hub 252 of the instrument250 to a point along a length of the body 254 of the instrument 250 atwhich the housing 202 is intended to attach to the body 254. When thehousing 202 is attached to the body 254 of the instrument 250, aproximal end of the housing 202 can be adjacent to a distal end of thepositioning element 220 such that the positioning element 220 extendslongitudinally along a length of the body 254 between the hub 252 andthe housing 202. The positioning element 220, by extending between thehub 252 and the housing 202, can be configured to prevent proximalmovement of the housing 202 relative to the instrument 250. Stateddifferently, the positioning element 220 can be designed to maintain thehousing 202 in a fixed spatial relation with respect to the instrument250.

The cutting device 200 (and optionally positioning element 220) can beused to form a skin incision in skin (e.g., skin 170) for receiving theinstrument 250, e.g., such that the instrument 250 can be received intoa target body lumen (e.g., a blood vessel). The instrument 250 can be,for example, a dilator, a catheter, a chest tube, or the like. In anembodiment, the instrument 250 can be a dilator that has a distal endconfigured to be inserted through the incision and a proximal endincluding a hub 252. The dilator can have a tapered distal end thatfacilitates insertion into and subsequent dilation of tissue and/orblood vessels deep to the level of the skin incision (e.g., deeper thana level of the skin incision in skin 170). In some embodiments, thedilator can range in size from about 3 French to about 12 French (i.e.,about 1 mm to about 4 mm), including all values and subranges inbetween. The instrument 250 can include a lumen that extends throughouta length of the instrument 250, i.e., through a length of the hub 252and a length of the body 254. The lumen can be configured to receive aguidewire, e.g., for steering or guiding the instrument 250 into thetarget body lumen.

In use, the cutting device 200 can be coupled to the instrument 250 suchthat the cutting element 210 can be configured to form an incision forreceiving the instrument 250, e.g., as part of the Seldinger technique.For example, a needle can be used to create a puncture site in tissue(e.g., tissue 170), and a guidewire can be inserted through the needleinto a body lumen (e.g., a blood vessel) deep to the insertion site atthe skin level. The needle can be removed, and the instrument 250 (e.g.,a dilator) with the housing 202 and optionally the positioning element220 coupled to its body 254, e.g., via coupling mechanisms 206 and/or222, can be slid over the guidewire until a distal end of the instrument250 contacts a surface of the skin. The cutting element 210 can then beactuated to form an incision in the skin that extends from the puncturesite and is sized to receive the instrument 250. The housing 202 can beattached to the instrument 250 at a specific location that enables thecutting element 210, when actuated, to form such an incision. Thepositioning element 250, for example, can be used to set a spacing ordistance between a proximal portion (e.g., hub 252) of the instrument250 and the housing 202, to ensure proper positioning of the housing 202relative to the instrument 250. Once the incision is formed, the housing202 and/or positioning element 220 can be removed (e.g., detached,decoupled) from the instrument 250, and the instrument 250 can beinserted through the incision into the body (e.g., and into a lumen orcavity). If the instrument 250 is a dilator (or dilators), the dilator(or dilators) can be used to dilate the tissue and/or blood vessels deepto the incision, and be subsequently withdrawn over the guidewireallowing the appropriately sized catheter (or other instrument) to beguided down the guidewire and placed in the body lumen.

In some embodiments, where the instrument 250 includes a tapered distalend, e.g., such as a dilator with a tapered distal end, the cuttingelement 210 can be supported such that it is angled toward the puncturesite (e.g., angled to follow the taper of the instrument 250), such thatthe cutting element 210 can form an incision that extends from thepuncture site, e.g., preventing any possibility of leaving a skinbridge.

Referring now to FIG. 3, a method 300 of performing a medical procedureon a subject using a cutting device, such as any of those describedherein (e.g., cutting device 100, 200, 500, 1200, and/or 1300), is shownand described.

The method 300 can be a method of forming an incision for receiving aninstrument (e.g., instrument 250). The instrument can be, for example, adilator. The method 300 can include forming, e.g., using a needle, apuncture site in tissue (e.g., skin 170), and advancing a guidewirethrough the needle into a body lumen, at 301. The needle can be removed,leaving the guidewire positioned traversing the puncture site. Theinstrument can define a lumen configured to receive the guidewire. Themethod 300 can optionally include coupling a cutting device to theinstrument, at 302. In some embodiments, a positioning element (e.g.,positioning element 120, 220 such as a spacer) can also be coupled tothe instrument to assist with appropriate positioning of the cuttingdevice on the instrument and to prevent proximal movement of the cuttingdevice relative to the instrument. In some embodiments, each of thecutting device and/or the positioning element can be reversibly coupledto the instrument such that each can be removed (e.g., detached,decoupled) from the instrument, e.g., when moved in a direction lateralto the longitudinal axis (e.g., a central longitudinal axis) of thedilator. In some embodiments, the method 300 may not include couplingthe cutting device to the instrument because the instrument may beprovided (e.g., packaged, sold, etc.) with the cutting devicepre-attached, to, but removable or detachable from, the instrument.

At 304, the method 300 can include advancing the instrument over andalong the guidewire toward the puncture site, e.g., until a distal endof the instrument is against a surface of the tissue. At 306, the method300 optionally includes actuating (e.g., via actuating assembly 104) acutting element (e.g., 110, 210) of the cutting device, e.g., to movethe cutting element from a retracted position to an extended position.In some embodiments, the cutting element can be angled (e.g., to followa tapered end of the instrument, such as the tapered end of a dilator),and therefore, actuation of the cutting element can cause the cuttingelement to extend radially inward towards a central longitudinal axis ofthe instrument. As described above with reference to FIG. 1, actuationof the cutting element can include release of a compressed spring, suchthat the spring transitions from a compressed state to an uncompressedstate to move the cutting element into the extended position.Alternatively, actuation of the cutting element can include moving(e.g., sliding) an actuation element that deploys the cutting element.For example, the cutting element can be moved from the retractedposition to the extended position by moving a slider of the cuttingdevice in a distal direction, e.g., using a thumb of a user when theslider is disposed on a side of the cutting device accessible by thethumb. When the cutting element has been actuated (e.g., deployed), thecutting element can be configured to form an incision in the tissue. Insome embodiments, the method 300 may not include actuating the cuttingelement, e.g., because the cutting element is supported on the cuttingdevice in an exposed manner and does not need to be actuated. In suchembodiments, the cutting device may include a cap or other componentthat may shield the cutting element during transport but be removed fromthe cutting element prior to use of the cutting device.

The cutting element, when actuated, can form an incision in the tissue,at 308. In some embodiments, the cutting device and the dilator can beadvanced toward the tissue after the cutting element has been extendedto form the incision. The incision can be formed such that it extendsfrom the puncture site and is sized to receive the instrument. Theincision, for example, can be formed to have a length that issubstantially equal to the diameter of the instrument. In someembodiments, the cutting device includes a depth control element (e.g.,depth control element 108), which can control a distance that thecutting element can extend beyond a distal end of the cutting deviceand/or a distance that the cutting element can be inserted into thetissue, thereby controlling a depth of the incision. For example, asurface of the cutting device (e.g., a surface of a housing of thecutting device) can be configured to contact the tissue once the cuttingelement has been inserted a set distance into the tissue. Alternativelyor additionally, one or more components of the cutting device may lockto prevent further extension of the cutting element beyond a distal endof the cutting device. In some embodiments, the cutting element can bemovable, after forming the incision, from its extended position back toits retracted position.

At 310, the method 300 optionally includes removing (e.g., decoupling,detaching) the cutting device and/or positioning element from theinstrument, e.g., by moving the cutting device and/or positioningelement in a direction lateral to the longitudinal axis of a body (e.g.,body 254) of the instrument.

At 312, the method 300 optionally includes, after forming the incision,advancing the instrument over the guidewire into the incision. In someembodiments, the instrument is advanced until a distal end of theinstrument is disposed within the body lumen. In some embodiments, whenthe instrument is a dilator, the instrument can be removed from theincision, and subsequent, larger instruments can be used to furtherdilate the subdermal tract to a final dilatation that allows a finalcatheter to be slid over the guidewire into the body lumen. The cathetercan then provide access to the body lumen, e.g., via a lumen of thecatheter.

In an example embodiment, a method can include disposing a dilator overa wire that has been inserted into a puncture site formed in tissue, thedilator including a proximal hub and an elongate body, the elongate bodyof the dilator having a cutting device reversibly coupled thereto;advancing the dilator with the cutting device toward the puncture site;moving a cutting element of the cutting device from (1) a fullyretracted position in which the cutting element is disposed within ahousing of the cutting device to (2) a fully extended position in whicha distal portion of the cutting element extends distally from thehousing to a distal end of the dilator; inserting the distal end of thedilator and the cutting element into the tissue such that the cuttingelement forms an incision extending from the puncture site; and movingthe cutting device laterally away from a longitudinal axis of thedilator while maintaining the dilator over the wire to decouple thecutting device from the elongate body of the dilator. The distal end ofthe dilator and the cutting element can be inserted into the tissueuntil a distal surface of the housing contacts the tissue and preventsfurther insertion of the cutting element into the tissue so that theincision has a length that is approximately equal to a diameter of acatheter to be placed through the incision. The cutting element can bemoved from the fully retracted position to the fully extended positionafter the distal end of the dilator is positioned against the puncturesite, or the cutting element can be moved from the fully retractedposition to the fully extended position while the dilator with thecutting device is advanced toward the puncture site. The cutting elementcan be disposed radially outward from a lumen of the dilator in thefully retracted and fully extended positions when the cutting device iscoupled to the elongate body of the dilator. The cutting element can bemoved from the fully retracted position to the fully extended positionin response to moving an actuation mechanism of the cutting device in adistal direction, the actuation mechanism disposed on a side of thecutting device opposite from a side of the cutting device coupled to thedilator. The method can also include moving, after forming the incision,the cutting element from the fully extended position back to the fullyretracted position, the cutting device being decoupled from the dilatorafter the cutting element is moved back to the fully retracted position.The method can also include advancing the dilator after decoupling thecutting device from the dilator to dilate the incision; removing thedilator from over the wire; and advancing the catheter over the wire andinto the incision. The method can also include moving, after forming theincision, a spacer laterally away from the longitudinal axis of thedilator while maintaining the dilator over the wire to decouple thespacer from the elongate body of the dilator. The spacer can bereversibly coupled to the elongate body of the dilator and be configuredto prevent proximal movement of the cutting device relative to thedilator.

Referring now to FIG. 4, a schematic diagram depicting components of asurgical system is shown and described. The components depicted in FIG.4 can be provided in a kit 401, which can be provided to a physician foruse during a surgical procedure. The kit 401 can be provided inpackaging 402, such as, for example, a box, a bag, etc. The packaging402 can be configured to keep the components of the surgical systemsterile prior to use. The surgical system can include an instrument 450and a cutting device 400, and optionally, a positioning element 420and/or additional instrument(s) 460.

The cutting device 400 can be functionally and/or structurally similarto other cutting device described herein (e.g., cutting device 100,200). For example, in some embodiments, the cutting device can include acutting element (e.g. cutting element 110, 210) configured to form anincision in tissue.

When included together in packaging 402, the cutting device 400 can bepre-coupled to the instrument 450 at a desired location, e.g., allowingthe creation of an incision in tissue. For example, the cutting device400 can be coupled to the instrument such that a cutting element (e.g.,cutting element 110, 210) of cutting device 400 can be configured toform an incision for receiving the instrument 450, e.g., an incisionthat extends from a puncture site and is sized for receiving theinstrument 450. Alternatively, the cutting device 400 and the instrument450 can be separately placed within the packaging 402, e.g., withinseparate inner compartments and/or containers.

One or more components of kit 401 can be configured to be disposed aftera single use. For example, the cutting device 400 can be configured forone-time use, e.g., the cutting device 400 can include one or morecomponents that lock after a single use.

The instrument 450 can be a dilator, a catheter, a chest tube, or othersurgical instrument. The instrument 450, similar to instrument 250described above, can define a lumen configured to receive a wire such asa guidewire that extends or is otherwise extendable through a puncturesite. In some embodiments, the kit 401 can optionally include anappropriately sized guidewire (not shown) for use with the instrument450. The instrument 450 can include a hub (e.g., similar to hub 252) ata proximal end and body (e.g., similar to body 254). The incision formedby the cutting device 400 can be sized to receive the instrument 450.For example, the incision can have a length that is substantially equalto a diameter of the instrument 450. In some embodiments, the kit 401can include the instrument 450 having a first diameter, and additionalinstruments 460 having diameters different than the first diameter. Forexample, the instrument 450 can be a dilator with a first dimeter, andan additional instrument 460 can be a dilator having a diameter greaterthan the first diameter of the dilator. In such embodiments, the kit 401can contain a set of dilators that progressively increase in size, e.g.,a progressive set of dilators. The dilators can increase in size from(1) a first diameter of the dilator that is configured to couple to thecutting device 400 to (2) a second diameter equivalent to a diameter ofthe final instrument (e.g., catheter) to be inserted into the incisionand into a target vessel. Each of the dilators can be used to dilate theincision to the size of the surgical instrument. In these instances, thecutting device can create an incisional length equal to the diameter ofthe final dilator/catheter/tube to be inserted.

In some embodiments, the kit 401 can include the positioning element420, which can be a spacer configured to assist with positioning thecutting device 400 relative to the instrument 450. Similar topositioning elements 120, 220, as described above, positioning element420 can extend longitudinally along a length of the instrument 450between a proximal portion (e.g., hub) of the instrument 450 to wherethe cutting device 400 couples to the instrument 450, thereby setting alocation of the cutting device 400 relative to the proximal portion ofthe instrument 450 and preventing proximal movement of the cuttingdevice 400 relative to the instrument 450. When included together in kit401, the positioning element 420 can be pre-coupled to the instrument450 along with the cutting device 400 such that the instrument 450 andthe cutting device 400 are ready for use. Alternatively, the positioningelement 420, cutting device 400 and instrument 450 can be includedseparately in kit 401 (e.g., in separate compartments or packages), suchthat a physician prior to and/or during a surgical operation must attachthe positioning element 420 and the cutting device 400 to the instrument450, permitting the cutting device 400 to form an incision in tissueduring the operation.

Referring now to FIGS. 5-10, various views of an example cutting device500 are shown and described. The cutting device 500 can includecomponents that are structurally and/or functionally similar to othercutting devices described herein, e.g., cutting devices 100 and 200. Forexample, the cutting device 500 can include a housing 502, an actuationassembly 504, a cutting element 510, a coupling mechanism 506, a depthcontrol element implemented as a tissue contact surface 501, apositioning element 520, and a coupling mechanism 522. The cuttingdevice 500 can be used with a medical device or instrument 550, asdepicted in FIGS. 9 and 10. The medical device 550, similar to othermedical devices described herein (e.g., medical device 250), can includea hub 552 and a body 554. The medical device 500 can be implemented as adilator that includes a tapered distal end 554 a. As shown in FIG. 9,the medical device 550 can define a lumen 556 configured to receive awire that extends or is otherwise extendable through a puncture site.

As shown in FIGS. 9-10, the cutting device 500 can be reversibly coupledto the medical device 550 via the coupling mechanism 506, similar tothat described with respect to the reversible coupling between thecutting device 200 and the instrument 250 via the coupling mechanism206. Further, the cutting device 500 can be designed such that, in adeployed position, a base (e.g., bottom edge 511 depicted in FIGS. 8 and9) of the cutting element 510 extends along a distal end of theinstrument 550 in contact with an outer surface of the instrument 550,and in particular, extends radially inwardly towards a centrallongitudinal axis of the instrument 550, e.g., at an angle 0 as shown inFIG. 10. The angle 0 can be equal to or greater than an angle of thetapered distal end 554 a of the instrument 550, with respect to thelongitudinal axis of the instrument 550. In some embodiments, when thecutting element 510 is extended, a distal end of the cutting element 510can terminate at (or substantially near) a distal end of the instrument550. The size of the incision formed by the cutting element can bedependent on an angle a of an outer cutting edge 512 of the cuttingelement 510 and a length that the cutting element 510 extends from adistal surface 501 of the cutting device 500, as further describedbelow.

The housing 502 can include multiple housing components that are heldtogether via one or more fasteners, e.g., screws 503, and/or adhesive.The housing 502 can define a volume, recess, or area for housing thecutting element 510 in a retracted or undeployed position, such as shownin FIG. 7. For example, the cutting element 510 can be retracted forshielding such as behind a distal surface 501 of the cutting device 500.As shown in FIG. 6, the housing 502 can be ergonomically shaped toenable a user (e.g., a physician) that is operating the device to holdthe housing 502 in a single handle and to actuate the actuationmechanism 504 to deploy the cutting element 510, i.e., the move thecutting element 510 from its undeployed positon (depicted in FIG. 7) toits deployed position (depicted in FIG. 8). In some embodiments,different configuration(s) of the housing 502 can be suited for use byright- and left-handed users.

The cutting element 510 can include an inner edge 511 and an outercutting edge 512, and can be designed to be movable via the actuationassembly 504 between a retracted position, such as shown in FIG. 7, andan extended position, such as shown in FIG. 8. The cutting element 510can include a locking mechanisms (e.g., a lock as described withreference to FIGS. 1-3, and internal surfaces as further describedbelow) that prevents the cutting element 510 from extending beyond theretracted position (e.g., further into the housing 502) or the extendedposition (e.g., further distal to the housing 502). As such, theretracted position is a fully retracted position and the extendedposition is a fully extended position. In the retracted position, thecutting element 510 can be fully disposed within the housing 502. In theextended position, a distal end of the cutting element 510 can terminateat (or substantially near) the distal end of the instrument 550. In someembodiments, a portion of the inner edge 511 can extend substantiallyalong the tapered distal end of the instrument 550 in contact with anouter surface of the instrument 550. The cutting element 510 can bemoved from the retracted position to the extended position andvice-versa. For example, such as shown in FIGS. 7-8, the cutting element510 can be moved to the extended position by actuation of the actuationassembly 504, implemented as a sliding component 505. The slidingcomponent 505 can be moved distally along a length of the cutting device500 to move the cutting element 510 into the extended position. In allpositions ranging from the retracted position to the extended position,the inner edge 511 of the cutting element 510 and a distal end of thecutting element 510 are disposed radially outward from the lumen of theinstrument 550. Stated differently, the cutting element 510 isconfigured to extend along the instrument 550 in contact with its outersurface but to not extend radially inward of an outer surface of theinstrument 550. The cutting element 510 can therefore form an incisionthat extends radially outward from a puncture site or a wire disposed inthe lumen of the instrument 550.

As depicted, the sliding component 505 can be attached (e.g., via a knobor protrusion 505 a) to an elastic component such as a spring 504 a thatis expandable to accommodate the movement of the sliding component 505and the cutting element 510 in the distal direction (e.g., to move thecutting element 510 into its extended position). When expanded, thespring 504 a can exert a force upon the sliding component 505, such thatwhen sliding component 505 is released, the spring 504 a canautomatically revert to its resting position and retract the cuttingelement 510 back into its retracted position in the housing 502.

The actuation assembly 504 can be designed to actuate the cuttingelement 510 from a retracted position to a deployed (e.g., extended)position to form an incision in and through skin (e.g., skin 170). Forexample, the actuation assembly 504 implemented as the sliding componentcan include an interface element 504 b (e.g., a protrusion) designed tointerface with (e.g., engage with) an interface element 510 a (e.g., arecess) of the cutting element 510, to thereby actuate and move thecutting element 510 longitudinally along the housing 502.

As described, the outer cutting edge 512 can be configured to cut tissueto form an incision. In some embodiments, the inner edge 511 in additionto the outer cutting edge 512 can be configured to cut tissue to formthe incision. Since a distal end of the inner edge 511 extends along adistal end of the instrument 550 (e.g., a tapered end of a dilator),i.e., is immediately adjacent or next to the distal end of theinstrument 550, having both the inner edge 511 and outer edge 512 beconfigured to cut tissue can further reduce the risk of leaving a skinbridge.

In some embodiments, the cutting device 500 may not include a spring,such as spring 504 a. In such embodiment, the user (e.g., physician) canmanually retract the cutting element 510 back into the housing 502 afterforming the incision by moving the sliding component 505 back in aproximal direction. While the cutting device 500 is depicted with anactuation assembly including a sliding component 505, it can beappreciated that any number or type of actuation mechanisms can be used,e.g., including a button, tab, lever, and the like, which can beactuated by a user to deploy the cutting element 510, such as describedabove with reference to cutting device 100. For example, the actuationassembly 504 can alternatively include a trigger that can be actuated torelease a pre-loaded or compressed spring or other elastic componentthat can generate a force to deploy and/or retract the cutting element510. In some embodiments, the actuation assembly 504 can alternativelyinclude hydraulic or pneumatic mechanisms for deploying and/orretracting the cutting element 510.

The depth control element can be designed to limit a depth of insertionor deployment of the cutting element 510. In an embodiment, the depthcontrol element can be implemented as a distal surface 501 of thecutting device 500. The distal surface 501 of the cutting device 500 canbe configured to contact a tissue surface and prevent further insertionof the cutting element 510 into the tissue. In particular, the cuttingdevice 500 mounted on the instrument 550 and with the cutting element510 extended can be slid down a length of a guidewire until the distalsurface 501 contacts the tissue surface and prevents further insertionof the cutting element 510 into the tissue. The size of the incision canbe controlled by a distance that the outer cutting edge 512 extends fromthe distal end 501 of the cutting device 500 and an angle a that theouter cutting edge 512 is angled with respect to the longitudinal axisof the instrument 550. In other embodiments, the depth control elementcan be implemented as a surface that interacts with a surface of atleast one of the cutting element 510 and/or the sliding component 505 ofthe actuation assembly 504 to control distal movement of the cuttingelement 510. For example, the depth control element can be an internalsurface of the housing 502 that engages a surface of the slidingcomponent 505 once the sliding component 505 has extended the cuttingelement 510 a set distance from its retracted position. Alternatively,the depth control element can include a stopper designed to interfacewith a surface of the cutting element 510 by abutment to controltranslation and a depth of insertion of the cutting element 510. In someembodiments, the depth control element can be integrated into and/orcoupled to the housing 502 and/or cutting element 510.

The coupling mechanism 506 can include one or more fasteners orcouplings designed to reversibly couple the housing 502 to theinstrument 550, such as that shown in FIGS. 9-10. For example, thecoupling mechanism 506 can include a flexible component such as a clipor clasp that is designed to reversibly couple the housing 502 of thecutting device 500 to the instrument 550 such as by gripping around thebody 54 of the instrument. The coupling mechanism 506 can be configuredto couple to the instrument 550 from a lateral direction, i.e., bymoving the housing 502 in a direction toward the longitudinal axis ofthe instrument 550, and similarly to decouple from the instrument 550 ina lateral direction. The coupling mechanism 506 can be integrated intoor otherwise used in conjunction with the housing 502 in any suitablemanner so as to enable and facilitate reversible coupling of the housing502 to the instrument 550, such as described herein. Once coupled to theinstrument 550, the coupling mechanism 506 can generate sufficientfriction against a surface of the body 554 of the instrument 550 toprevent movement (e.g., sliding and/or rotation) of the cutting device500 relative to the instrument 550. As depicted in FIGS. 9 and 10, thecoupling mechanism 506 can include multiple attachment points to reducethe risk of movement due to a torsional force. In some embodiments, thecoupling mechanism 506 can be configured to couple the housing 502 to aspecific size of instrument, e.g., a dilator having a specific diameterand length. In other embodiments, the coupling mechanism 506 can beadjustable (e.g., via tightening and/or loosening of a screw or otheradjustment mechanism, or due to a malleability of the couplingmechanism) to adapt the coupling mechanism 506 for use with differentsized instruments.

The positioning element 520 can be used with the cutting device 500 tomaintain the housing 502 in a fixed spatial relation with respect to themedical device 550. For example, the positioning element 520 can beimplemented as a spacer having a handling tab 521 to facilitate coupling(e.g., by a user) of the positioning element 520 with the instrument550, e.g., via coupling mechanism 522. The spacer can be placed suchthat it extends from the hub 552 (e.g., is adjacent to the hub 552) to aproximal end of the housing 502, thereby defining a set spacing betweenthe hub 552 and the housing 502, as shown in FIG. 10. The spacer can beconfigured for use with a specific size of the instrument 550, e.g., adilator having a specific diameter and length.

The coupling mechanism 522 can be designed to reversibly couple thepositioning element 520 to the instrument 550. For example, the couplingmechanism 522 can include a flexible component such as a clip or claspthat is designed to removably couple the positioning element 520 to theinstrument 550 such as by interference fit, press fit, friction fit, andthe like (e.g., by gripping around the body 554 of the instrument 550.The coupling mechanism 522 can be integrated into or otherwise used inconjunction with the positioning element 520 so as to enable andfacilitate reversible coupling of the positioning element 520 to theinstrument 550, such as described herein. The positioning element 520and the housing 502 can be separately and individually attachable to andremovable from the instrument 550.

In use, cutting device 500 including the housing 502 and the positioningelement 520 can be coupled (e.g., attached) to the body 554 of theinstrument 550. The instrument 550 can be slid down a length of aguidewire that is positioned in a puncture site, e.g., a puncture siteformed as part of a surgical procedure using the Seldinger technique.The instrument 550 can be slid down the guidewire until a distal end ofthe instrument 550 is positioned adjacent to the skin with the puncturesite. The cutting element 510 can be positioned in a retracted position(as shown in FIG. 7) while the instrument 550 is slid down a length ofthe guidewire. Once the instrument 550 is in position against the skin,the cutting device 500 can then be actuated, e.g., by sliding thesliding component 505 toward the puncture site to form an incision withthe cutting element 510 that extends from the puncture site and is sizedto receive the instrument 550. Optionally, the cutting element 510 canbe retracted back into the housing 502, and the housing 502 and/or thepositioning element 520 can be removed (e.g., decoupled, detached) fromthe instrument 550 and set aside. The instrument 550 can then beinserted into the incision, e.g., to dilate the tissue below theincision and/or be placed within a body lumen to provide vascular accessto the body lumen.

Referring now to FIGS. 12A-12C, views of another example cutting device1200 are shown and described. FIG. 12A depicts a side view of thecutting device 1200 coupled to an instrument 1250 (e.g., a dilator).FIG. 12B schematically illustrates a distal end of the cutting device1200 and the instrument 1250. And FIG. 12C schematically illustrates across-sectional view of a distal end portion of the cutting device 1200and the instrument 1250. The cutting device 1200 can include componentsthat are structurally and/or functionally similar to other cuttingdevices described herein. For example, the cutting device 1200 caninclude a housing 1202, a cutting element 1210, and a coupling mechanism1206. The cutting device 1200 can be used with the instrument 1250,similar to other instruments described herein.

As depicted in FIG. 12A, the instrument 1250 can be implemented as adilator having a body 1254 that includes a tapered distal end 1254 a,and a hub 552 at a proximal end. The instrument 1250 can define a lumenconfigured to receive a wire such as guidewire 1253 that extends or isotherwise extendable through a puncture site. In addition, theinstrument 1250 can include a slot or opening 1256 that extends along adistal portion of the instrument 1250 for receiving the cutting element1210 therethrough, as further described below.

The cutting device 1200 can be configured to reversibly couple to theinstrument 1250 and can include a proximal end configured to abut thehub 1252 of the instrument 1250 when coupled thereto, as describedherein. In some embodiments, the cutting device 1200 may be designed tomove or slide longitudinally along a body 1254 of the medical device1250.

The housing 1202 can support the cutting element 1210. For example, thehousing 1202 can include a clamp, protuberance, knob, bump, or otherattachment mechanism for holding and supporting the cutting element1210. The cutting element 1210 can include an inner edge (not depicted)and an outer cutting edge 1211. In some embodiments, the inner edge inaddition to the outer cutting edge 1211 can be a cutting edge configuredto cut tissue. The cutting element 1210 can be translated along theinstrument 1250 by translation of the housing 1202 along the instrument1250, such that the inner edge moves along a length of the slot 1256 inthe instrument 1250. The cutting element 1210 can be translated distallyalong a length of the instrument 1250 such that it extends into tissue.In some embodiments, the housing 1202 can be designed to be slid ortranslated along the instrument 1250 by manually applied force (e.g.,via a hand of a user).

As depicted in FIGS. 12B and 12C, the slot 1256 enables a portion of thecutting element 1210 (e.g., an inner edge of the cutting element 1210)to extend into an inner lumen of the instrument 1250 such that thecutting element 1210 abuts or is near the wire 1253. The cutting element1210 can then be slid along the slot 1256 in a distal direction to forman incision that extends from a puncture site in which the wire 1253 isdisposed. By enabling the cutting element 1210 to extend into the innerlumen of the instrument 1250 to the wire 1253, the slot 1256 preventsthe formation of a skin bridge. As depicted in FIG. 12C, the slot 1256can have a width that is sufficiently large to permit the cuttingelement 1210 to extend into the inner lumen of the instrument 1250 butless than a diameter of the wire 1253 such that the wire 1253 cannotexit from the inner lumen of the instrument 1250 via the slot 1256.

In some embodiments, the cutting device 1200 can include a depth controlelement 1208 that is designed to limit a depth of insertion ordeployment of the cutting element 1210. For example, the depth controlelement 1208 can include a surface of a protrusion (e.g., aprotuberance, knob, bump, etc.) designed to contact the skin of asubject to limit further insertion of the cutting element 1210 into theskin. The depth control element 1208 can be integrated into and/orcoupled to the housing 1202. Alternatively, the depth control element1208 can be integrated into and/or coupled to the cutting element 1210.

The coupling mechanism 1206 can reversibly couple the housing 1202 tothe instrument. For example, the coupling mechanism 1206 can include aflexible component such as a clip or clasp that is designed to removablycouple the housing 1202 to the instrument 1250 such as by interferencefit, press fit, friction fit, and the like. The coupling mechanism 1206can be integrated into or otherwise used in conjunction with the housing1202 so as to enable and facilitate reversible coupling of the cuttingdevice 1200 to the instrument 1250, such as described herein. In someembodiments, for example, the coupling mechanism 1206 can include twoattachment points to prevent movement of the cutting device 1200 withrespect to the instrument 1250 due to torsional forces.

A proximal portion of the cutting device 1200 can function as apositioning element, e.g., be designed to maintain the housing 1202 in afixed spatial relation with respect to the instrument 1250. For examplethe proximal portion of the housing 1202 can extend to the hub 1252 ofthe instrument 1250 to define a spacing between the hub 1252 and thecutting element 1210 and to thereby ensure specific positioning of thecutting device relative to a proximal end of the instrument 1250.

Referring now to FIGS. 13-14C, various views of another example cuttingdevice 1300 are shown and described. The cutting device 1300 can beimplemented as an instrument (e.g., a dilator) that includes one or morecutting elements 1310. The cutting device 1300 can include componentsthat are structurally and/or functionally similar to other cuttingdevices described herein (e.g., cutting device 100, 200, etc.). Forexample, the cutting device 1300 can include a housing 502, a cuttingelement 1310, and a depth control element 1308. Similar to otherdilators described herein, the cutting device 1300 can include aproximal hub 1352 and an elongate body (e.g., housing 1302) that definesa lumen 1356 for receiving a guidewire that extends or is otherwiseextendable through a puncture site.

The cutting device 1300 is designed to receive a guidewire (e.g., wire1353) within the lumen 1356 of the device and to slide along a length ofthe guidewire. The housing 1302 at its distal end can support one ormore cutting element(s) 1310. Each of the cutting element(s) 1310 caninclude an outer cutting edge. The outer cutting edge can be configuredto form an incision in tissue, where the incision extends from apuncture site in which the guidewire is disposed. The outer cuttingedges can be configured to form a continuous incision that issymmetrically disposed about a puncture site. As depicted in FIGS. 14Aand 14B, the cutting element(s) 1310 are configured as flat blades.

The cutting device 1300 can include a depth control element 1308 that isdesigned to control a depth of insertion of the cutting element(s) 1310.For example, the depth control element can include a stopper (e.g., aprotuberance, knob, bump, etc.) designed to contact a surface (e.g.,skin or tissue of a subject) to limit further insertion of the cuttingelement(s) 1310 into the tissue. The depth control element 1308 can beintegrated into and/or coupled to the housing 1302 and/or cuttingelement(s) 1310.

FIG. 15 depicts the cutting device 1300 being used to form an incisionin skin. After a wire 1353 has been positioned in a puncture site formedin the skin, the cutting device 1300 can be slid down along a length ofthe wire 1353 until the depth control element 1308 of the cutting device1300 contacts a surface of the skin (as depicted in FIG. 15). Thecutting element 1310 of the cutting device 1300 can form an incision inthe skin that is sized according to a position of the depth controlelement 1308 relative to a distal end of the cutting device 1300. As thecutting elements 1310 are adjacent to the lumen 1356 of the cuttingdevice 1300 at its distal end, the cutting elements 1310 form anincision that extends from the puncture site without a skin bridge.

Referring now to FIGS. 16A-16D, various views of an example cuttingdevice 1600 are shown and described. The cutting device 1600 can includecomponents that are structurally and/or functionally similar to any ofthe other cutting devices described herein, e.g., cutting devices 100,200, 500, 1200, 1300. For example, the cutting device 1600 can include ahousing 1602, an actuation assembly 1604, a cutting element 1610, acoupling mechanism (not depicted), a depth control element (notdepicted), and/or a positioning element (not depicted). The cuttingdevice 1600 can be used with a medical device or instrument (notdepicted), such as a dilator, a catheter, or any others describedherein.

The cutting element 1610 can include a single or multiple edges that areformed as cutting edges, which can be configured to cut tissue to forman incision. For example, in an embodiment, both an inner and outer edgeof the cutting element 1610 can be cutting edges. Having both inner andouter edges be formed as cutting edges can reduce a risk of leaving askin bridge. The actuation assembly 1604 can include a guide 1604B and afollower 1604A. The follower 1604A can be configured to be attached toor fixed, mated, or coupled, with the cutting element 1610 in anysuitable manner. The actuation assembly 1604 can also include anactuator (e.g., a slider, button, tab, lever, not depicted) that can bemoved (e.g., slid along a length of the housing 102) such as by a user.In some embodiments, the guide 1604B and the follower 1604A can beconfigured to transform movement of the actuator (e.g., caused by anapplied force, e.g., by a user) into a combination of linear and lateralmotion of the cutting element 1610. In some embodiments, the guide 1604Bcan be a cam, such as in the form of a surface, slot, channel, ordepression defined in the housing 1602. In some embodiments, the guide1604B can include and/or define one or more of a straight path orsection and a curved path or section. In some embodiments, the follower1604A can be a cam follower such as in the form of a roller, bearing, orthe like, shaped and designed to move along and follow a path (e.g.,slot, channel, depression) defined by the guide 1604B. The follower1604A, when moving along the guide 1604B, is confined to motion limitedby the path defined by guide 1604B. Stated differently, a cam (e.g.,guide 1604B) and cam follower (e.g., follower 1604A) can be used toprovide a combination of linear movement and lateral movement of acutting element 1610.

As depicted in FIG. 16B, movement 1619A of the actuator of the actuationassembly 1604 can be transferred and applied to the follower 1604A, towhich the cutting element 1610 is attached. The movement 1619A can be alinear movement or motion corresponding to the motion of the actuator.As depicted in FIG. 16C, continued movement 1619B of the actuator can betransferred and applied to the follower 1604A. The continued movement1619B can be a linear movement or motion corresponding to the motion ofthe actuator. The guide 1604B in conjunction with the follower 1604A cantransform the linear motion of the actuator into a combination of linearand lateral motion of the cutting element 1610.

As depicted in FIG. 16D, the movement 1619A of the actuator istransferred and applied to the follower 1604A to cause a motion of thecutting element 1610. The continued movement 1619B of the movablecomponent is similarly transferred and applied to the follower 1604Asuch that, upon traversal of and movement past a predetermined point(e.g., coinciding with a transition from a straight section to a curvedsection of the guide 1604B), the follower 1604A along with the cuttingelement 1610 are subjected to lateral motion 1619C. FIG. 16D depicts anexample motion of the follower 1604A and the cutting element 1610. Thelateral motion 1619C can include, for example, a hacking or swingingmotion.

More specifically, movements 1619A and 1619B of the actuator (of theactuation assembly 1604) cause movement of the follower 1604A along theguide 1604B, such that the movement along a curved section of the guide1604B causes the lateral motion 1619C of the cutting element 1610. Whilethe follower 1604A is in the straight section of the guide 1604B, thefollower 1604A and cutting element 1610 can move (e.g., slide) in astraight path. When the follower reaches the curved section of the guide1604B, the follower 1604A and cutting element 1610 can begin to movelaterally or radially as the follower 1604A continues to move along theguide 1604B. As shown in FIGS. 16A-16D, to cause the motion of thefollower 1604A, including both the straight and curved movement, theactuator can move in a straight path.

FIGS. 18-23 depict an example cutting device 1800. The cutting device1800 can include components that are structurally and/or functionallysimilar to other cutting devices described herein, e.g., cutting device100, 200, and 500. For example, the cutting device 1800 can include ahousing 1802, an actuation mechanism 1804, a cutting element 1810, acoupling mechanism 1806, and a depth control element implemented as atissue contact surface 1801. While not depicted, cutting device 1800 canbe used with a positioning element but can also be used alone.

The cutting device 1800 is reversibly coupleable to a medical device,e.g., a dilator 1850 as shown in FIGS. 20-22, via the coupling mechanism1806. The coupling mechanism 1806 includes two fastening or couplingpoints 1806 a, 1806 b. At each coupling point 1806 a, 1806 b, one ormore plugs or gripping mechanisms 1807 a, 1807 b (which can be rigid orflexible) can be used to reversibly couple to the dilator 1850.Alternatively or additionally, other types of coupling elements, e.g.,clamps, clips, magnets, etc., can also be used to grip the dilator 1850.The coupling mechanism 1806 can be configured to couple to the dilator1850 from a lateral direction, e.g., by moving the cutting device 1800in a direction toward the longitudinal axis of the dilator 1850, andsimilarly to decouple from the dilator 1850 in a lateral direction.While not depicted in FIGS. 20-22, the dilator 1850 can include aproximal end including a hub (e.g., as described with reference toinstrument 250 depicted in FIG. 2). Accordingly, the cutting device1800, by being laterally coupleable and decoupleable from the dilator1850, is capable of being separated from the dilator 1850 even while thedilator 1850 is disposed over a guidewire that is disposed within apatient. Once coupled to the dilator 1850, the coupling mechanism 1806can generate sufficient friction against the dilator 1850 to preventmovement (e.g., sliding and/or rotation) of the cutting device 1800relative to the dilator 1850. The coupling mechanism 1806 includes morethan one coupling point (i.e., two coupling points 1806 a, 1806 b) suchthat the coupling points collectively prevent pivoting and/ordisplacement of the cutting device 1800 relative to the dilator 1850.The dilator 1850 itself may have a degree of flexibility, and thereforehaving multiple points of coupling can ensure that the dilator 1850remains aligned with the cutting device 1800 during use.

In the embodiment depicted, the coupling point 1806 a can be located ator near a distal or front end of the cutting device 1806, to furtherensure alignment between a cutting element 1810 of the cutting deviceand a longitudinal axis of the dilator (e.g., by reducing the risk ofdisplacement between the end of the dilator 1850 and the cutting device1800). Such alignment ensures that the cutting device 1800 does not forman incision that is offset from the puncture site, as depicted in FIG.17A. In some embodiments, one or more components of the couplingmechanism 1806 can be controlled, e.g., via a mechanical or electricalactuator, to open and/or close to couple and decouple the cutting device1800 to the dilator 1850. While two coupling points 1806 a, 1806 b aredepicted in the figures, it can be appreciated that any number ofcoupling points or a continuous coupling point can be used to couple thecutting device 1800 to a medical instruction such as dilator 1850.

The housing 1802 can define a space of volume for receiving and housinga cutting element 1810 of the cutting device 1800. The housing 1802 canbe ergonomically sized and shaped to enable a user (e.g., a physician)that is operating the device to hold the housing 1802 in a single handleand to actuate the actuation mechanism 1804 to deploy the cuttingelement 1810. In some embodiments, the housing 1802 can include certainridges or indentations 1880, as well as other like features, tofacilitate gripping by a user. The housing 1802 can support theactuation mechanism 1804 in a location where it can be easilymanipulated by a finger of a user (e.g., an index finger or thumb of auser). In some embodiments, the housing 1802 can support the actuationmechanism 1804 along a side of the cutting device 1800 that faces awayfrom the dilator 1850 when the two are coupled together. For example,the housing 1802 can support the actuation mechanism 1800 on a side ofthe cutting device 1800 that is opposite from the side including thecoupling mechanism 1806 or on a side of the cutting device 1800 furthestaway from the dilator 1850 in a direction radial to the longitudinalaxis of the dilator 1850. The actuation mechanism 1804, as disposed, canbe capable of being operated by both left and right handed users. Inalternative embodiments, the actuation mechanism 1804 can be supportedby the housing in other locations along its surface, e.g., such as theactuation mechanism 504 of the cutting device 500.

The cutting element 1810 is moveable between a first position, i.e., afully retracted or undeployed position, and a second position, i.e., afully extended or deployed position. Cross-sectional views of theretracted position are depicted in FIGS. 22 and 23, and views of theextended position are depicted in FIGS. 18, 20, and 21. In the retractedposition, the cutting element 1810 can be disposed entirely within thehousing 1802, e.g., such that any cutting surfaces or edges of thecutting element 1810 are shielded within the housing 1802. In theextended position, the cutting element 1810 can extend out from a distalsurface 1801 of the cutting device 1800. The cutting element 1810 caninclude an inner edge 1811 and an outer edge 1812. In some embodiments,both the inner and outer edges 1811, 1812 can be cutting edges, e.g.,designed to cut tissue. In some embodiments, the outer edge 1812 can bea cutting edge while the inner edge 1811 can be a non-cutting edge. Insome embodiments, one or both of the inner and outer edges 1811, 1812can include a non-cutting portion and a cutting portion.

The cutting element 1810, in the fully extended position, can have aportion of its inner edge 1811 extend along or substantially along adistal end 1850 a of the dilator 1850 in contact with an outer surfaceof the distal end 1850 a, as depicted in FIG. 21. Similar to thatdescribed above with reference to cutting element 510 of cutting device500, the cutting element 1810 can be angled such that its inner edge1811 extends along the outer surface of the distal end 1850 a of thedilator 1850. In the fully extended position, the distal end 1810 a ofthe cutting element 1810 terminates at (or substantially near) thedistal end of the dilator 1850. In some embodiments, the cutting device1800 can include a spring 1840 (e.g., a torsion spring, an elasticspring, etc.) that applies a force upon the cutting element 1810 thatpushes the cutting element 1810 against an outer surface of the dilator1850. The force applied by the spring 1840 can further ensure that theinner edge 1811 of the cutting element 1810 is disposed against theouter surface of the dilator 1850. The dilator 1850 includes a lumen1856 for receiving a guidewire, e.g., such as a guidewire being used ina Seldinger procedure. When used in a Seldinger procedure, the dilator1850 can be slid down a length of the guidewire to a puncture site, andthe cutting element 1810 can be extended to form an incision. Thecutting element 1810, by being disposed against an outer surface of thedilator 1850 and with its distal end 1810 a extending to the distal endof the dilator 1850, ensures that the incision formed by the cuttingelement 1810 extends from the puncture site.

The size of the incision formed by the cutting element 1810 can be sizedto a particular medical instrument, e.g., the dilator 1850. The size ofthe incision can be controlled by a length that the cutting element 1810extends and an angle at which the outer cutting edge is angled relativeto the longitudinal axis of the dilator 1850, as described in moredetail above with respect to cutting element 510 of cutting device 500.The cutting device 1800 can include a depth control element implementedas a tissue contacting surface 1801. The surface 1801 can be configuredto contact the tissue surface near the puncture site to prevent furtherinsertion of the cutting element 1800 into the tissue. Therefore, inuse, the cutting device 1800 mounted on the dilator 1850 can be sliddown a length of the guidewire until the distal surface 1801 contactsthe tissue surface and prevents further insertion of the cutting element1810 into the tissue. The cutting element 1810 can be extended prior to,during, or after sliding the cutting device 1800 with the dilator 1850down along the length of the guidewire to form the incision.

The actuation mechanism 1804 can be used to extend and retract thecutting element 1810. In some embodiments, the cutting device 1800 caninclude a locking mechanism that locks or prevents movement of theactuation mechanism 1804 until the actuation mechanism is depressed. Thelocking mechanism can prevent unintentional movement of the actuationmechanism 184 and therefore unintentional movement of the cuttingelement 1810. In some embodiments, the locking mechanism can include atrack or guide 1846, a spring 1842 (e.g., a torsion spring, elasticspring, etc.), and a plate or other structural component 1844 thatdefines one or more openings 1844 a, 1844 b. The actuation mechanism1804 can include one or more protrusions or detents 1805 a, 1805 b. Thespring 1842 can be configured to apply a force against the actuationmechanism 1804 that positions the detents 1805 a, 1805 b of theactuation mechanism 1804 within the openings 1844 a, 1844 b of the plate1844. The actuation mechanism 1804 with the detents 1805 a, 1805 b sopositioned is prevented from moving, e.g., by detents 1805 a, 1805 bcoming into contact with opposing surfaces of the plate 1844.

In use, the actuation mechanism 1804 can be depressed into the housing1802 (as shown by arrow 1819) such that the detents 1805 a, 1805 b movethrough the openings 1844 a, 1844 b and into the track 1846. Forexample, a user can apply sufficient force to overcome the force appliedby the spring 1842 to depress the actuation mechanism 1804. Theactuation mechanism 1804 can then be pushed forward (i.e., toward adistal surface 1801 of the cutting device 1800) with the detents 1805 a,1805 b travelling along the track 1846, thereby extending the cuttingelement 1810. The actuation mechanism 1804, without first beingdepressed downward into the housing 1802, is prevented from moving suchthat accidental taps against the actuation mechanism 1804 do not causeunintentional extension of the cutting element 1810.

While various embodiments have been described and illustrated herein,those of ordinary skill in the art will readily envision a variety ofother means and/or structures for performing the function and/orobtaining the results and/or one or more of the advantages describedherein, and each of such variations and/or modifications is deemed to bewithin the scope of the embodiments described herein. More generally,those skilled in the art will readily appreciate that all parameters,dimensions, materials, and configurations described herein are meant tobe exemplary and that the actual parameters, dimensions, materials,and/or configurations will depend upon the specific application orapplications for which the inventive teachings is/are used. Thoseskilled in the art will recognize, or be able to ascertain using no morethan routine experimentation, many equivalents to the specific inventiveembodiments described herein. It is, therefore, to be understood thatthe foregoing embodiments are presented by way of example only and that,within the scope of the appended claims and equivalents thereto; andthat embodiments may be practiced otherwise than as specificallydescribed and claimed without departing from the scope and spirit of thepresent disclosure. Embodiments of the present disclosure are directedto each individual feature, system, article, material, kit, and/ormethod described herein. In addition, any combination of two or moresuch features, systems, articles, materials, kits, and/or methods, ifsuch features, systems, articles, materials, kits, and/or methods arenot mutually inconsistent, is included within the inventive scope andspirit of the present disclosure.

As used herein, the terms “about” and/or “approximately” when used inconjunction with values and/or ranges generally refer to those valuesand/or ranges near to a recited value and/or range. In some instances,the terms “about” and “approximately” may mean within ±10% of therecited value. For example, in some instances, “approximately a diameterof an instrument” may mean within ±10% of the length of the instrument.The terms “about” and “approximately” may be used interchangeably.

Also, various concepts may be embodied as one or more methods, of whichan example has been provided. The acts performed as part of the methodmay be ordered in any suitable way. Accordingly, embodiments may beconstructed in which acts are performed in an order different thanillustrated, which may include performing some acts simultaneously, eventhough shown as sequential acts in illustrative embodiments.

1. An apparatus, comprising: a cutting device including: a housing; aset of couplers configured to reversibly couple the cutting device to adilator, the dilator disposable about a wire that has been inserted intoa puncture site formed in tissue; a cutting element movable between (1)a fully retracted position in which the cutting element is disposedwithin the housing and (2) a fully extended position in which a distalend of the cutting element extends distally from the housing and isconfigured to form an incision in the tissue that extends from thepuncture site, the cutting element configured to be disposed radiallyoutward from a lumen of the dilator in the fully retracted and fullyextended positions; and an actuation mechanism supported by the housing,the actuation mechanism configured to move the cutting element into theextended position when the cutting device is coupled to the dilator andthe dilator is disposed about the wire such that the cutting element canform the incision.
 2. The apparatus of claim 1, wherein the housingincludes a distal surface configured to limit a depth of insertion ofthe cutting element into the tissue such that the incision has a lengththat is approximately equal to a diameter of a catheter to be placedthrough the incision.
 3. The apparatus of claim 1, wherein the actuationmechanism is supported on a side of the housing that faces away from thedilator when the cutting device is coupled to the dilator.
 4. Theapparatus of claim 1, wherein the set of couplers and the actuationmechanism are supported on opposite sides of the housing.
 5. Theapparatus of claim 1, wherein the cutting device further includes aspring configured to apply a force on the cutting element such that thecutting element is pressed against an outer surface of a tapered distalend of the dilator.
 6. The apparatus of claim 1, wherein the set ofcouplers includes a first coupler disposed at or near a distal end ofthe cutting device and a second coupler disposed at or near a proximalend of the cutting device.
 7. The apparatus of claim 1, wherein thecutting element includes (1) an inner edge having a portion that extendsalong a tapered distal end of the dilator in contact with an outersurface of the dilator and (2) a distal end that terminates at a distalend of the dilator, when the cutting element is in the extended positionand the cutting device is coupled to the dilator.
 8. The apparatus ofclaim 1, wherein: the cutting device further includes a springconfigured to apply a force on the actuation mechanism to place theactuation mechanism in a locked position, the actuation mechanismincludes a set of detents configured to engage a set of locking surfaceswithin the housing when the actuation mechanism is in the lockedposition to prevent movement of the actuation mechanism, the actuationmechanism is movable from the locked position to an unlocked position inresponse to being moved toward the housing, the actuation mechanism isconfigured to slide along a track within the housing when the actuationmechanism is in the unlocked position to move the cutting element fromthe retracted position to the extended position.
 9. The apparatus ofclaim 1, wherein the cutting element includes outer and inner edges thatextend toward a longitudinal axis of the dilator when the cutting deviceis coupled to the dilator.
 10. The apparatus of claim 1, wherein the setof coupling elements is configured to decouple from the dilator when thedilator is disposed about the wire and the cutting device is moved in adirection lateral to a longitudinal axis of the dilator.
 11. Theapparatus of claim 1, wherein the set of couplers is a first set ofcouplers, the apparatus further comprising: a spacer configured toprevent proximal movement of the housing relative to the dilator, thespacer including a second set of couplers configured to reversiblycouple the spacer to the dilator, the spacer sized to extendlongitudinally along the dilator from a distal end of a proximal hub ofthe dilator to a most proximal coupler from the first set of couplerswhen the spacer and the cutting device are coupled to the dilator.
 12. Akit, comprising: a dilator including a proximal hub and an elongatebody, the dilator disposable about a wire that has been inserted into apuncture site formed in tissue; and a cutting device reversiblycoupleable to the dilator, the cutting device including: a housing; aset of couplers configured to (1) couple to the elongate body of thedilator and (2) decouple from the elongate body of the dilator when thedilator is disposed about the wire and the cutting device is movedlaterally away from a longitudinal axis of the dilator; and a cuttingelement movable between (1) a fully retracted position in which thecutting element is disposed within the housing and (2) a fully extendedposition in which a distal end of the cutting element extends distallyfrom the housing and is configured to form an incision in the tissuethat extends from the puncture site, the cutting element configured tobe disposed radially outward from a lumen of the dilator in the fullyretracted and fully extended positions.
 13. The kit of claim 12, whereinthe set of couplers is not configured to couple to the wire.
 14. The kitof claim 12, wherein the set of couplers is configured to couple to theelongate body having a diameter of about 1 mm to about 4 mm.
 15. The kitof claim 12, wherein the cutting device further includes an actuationmechanism supposed by the housing, the actuation mechanism configured tomove the cutting element into the extended position when the cuttingdevice is coupled to the dilator and the dilator is disposed about thewire such that the cutting element can form the incision.
 16. The kit ofclaim 15, wherein the set of couplers and the actuation mechanism aresupported on opposite sides of the housing.
 17. The kit of claim 15,wherein: the cutting device further includes a spring configured toapply a force on the actuation mechanism to place the actuationmechanism in a locked position, the actuation mechanism includes a setof detents configured to engage a set of locking surfaces within thehousing when the actuation mechanism is in the locked position toprevent movement of the actuation mechanism, the actuation mechanism ismovable from the locked position to an unlocked position in response tobeing moved toward the housing, the actuation mechanism is configured toslide along a track within the housing when the actuation mechanism isin the unlocked position to move the cutting element from the retractedposition to the extended position.
 18. The kit of claim 12, furthercomprising a catheter configured to be placed through the incision intoa target vessel, wherein the housing includes a distal surfaceconfigured to limit a depth of insertion of the cutting element into thetissue such that the incision has a length that is approximately equalto a diameter of the catheter.
 19. The kit of claim 12, wherein thedilator is included in a progressive set of dilators, the kit furthercomprising: a catheter configured to be placed through the incision intoa target vessel; and the progressive set of dilators, each dilator fromthe progressive set of dilators disposable about the wire to dilate theincision, the progressive set of dilators increasing in size from adiameter of the dilator to a diameter of the catheter.
 20. The kit ofclaim 12, wherein the cutting device further includes a springconfigured to apply a force on the cutting element such that the cuttingelement is pressed against an outer surface of a tapered distal end ofthe dilator.